Dispersants have several functions in producing ceramic materials via a method which includes spray drying and dry compressing. One function is to reduce the tendency of particles in the slurry to settle and stabilize the slurry. Another function is to facilitate maximization of the concentration of solids in the slurry before spray drying in order to reduce the energy required in the drying process. A third function is to reduce the viscosity of the slurry so that the slurry may be more easily pumped. A fourth function is to enhance green strength of a compressed ceramic aggregate structure formed from the spray dried particles. In performing these functions, dispersants affect the morphology and composition of the spray dried particles, which in turn govern the properties of the green and fired ceramics which are ultimately produced.
Ceramic oxide materials are conventionally produced from powdered ceramic oxides such as magnesia, alumina, and zirconia. On a commercial scale, the powdered oxides are usually mixed in a slurry along with additives, such as dispersants and binders, and spray dried. The dried particles are commonly compressed into an aggregate structure having a desired shape, usually by means of a hydraulic press. The aggregate structures are subsequently heated to sinter the individual particles into a cohesive mass which may approximate a monolithic ceramic phase.
In the past, ceramic manufacturers have relied on dispersants such as lignosulfonates, polyacrylates, and poly(methacrylates). However, a need still exists for a method utilizing an improved dispersant for use in preparing ceramic oxide materials.